The goal of both of these contracts are to provide support of National Toxicology Program (NTP) hazard identification activities targeted toward the prevention of diseases or adverse effects caused by environmental exposure to chemical or physical agents. Toxicity testing is an important aspect of public health research in that it serves to identify chemicals that are hazardous to human health. Proper chemical analyses are required to ensure that, in toxicity studies, the test species are exposed to the prescribed chemicals at the specified dose concentrations. These contracts contribute to the ability of toxicity studies to provide evidence of heightened cancer risk along with other toxicological outcomes, by providing characterization of the chemicals studied, confirmation of the dose levels administered, and internal dose determinations. This information is critical to evaluation of toxicity tests and development of sound, scientific conclusions about the potential toxicity of the study chemical in the test species and ultimately supports the risk assessment efforts of National Toxicology Program and other federal agencies. With internal dose information provided by this contract, extrapolations to humans can be made so that the public can be adequately informed about risk factors arising from exposure to studied chemicals. Both of these contracts are used for determining the toxicological potential of selected test agents for the National Toxicology Program (NTP). This contract is used for determining the toxicological potential of selected test agents for the National Toxicology Program (NTP). A combination of any of the following studies may be conducted using these contracts. They are: Acute studies, Prechronic and chronic studies (14-day, 28-day, and 90-day, and two year studies in various strains of rats and mice), Perinatal studies with gestational and postnatal exposure, studies to evaluate QT Prolongation via implantable telemetry. Some of the examples of the endpoints evaluated in these studies are: Histopathology, Differential Gene Expression using Microarray, Insertional mutagenesis, Clinical Chemistry, Hematology, QPCR etc. The routes of administration are oral (gavage, dosed water and dosed feed), IV and IP injections, and submandibular cannulation.